Pen cap



FIG. 1 is a perspective view of pen cap showing the design;

FIG. 2 is a front side view thereof;

FIG. 3 is a rear side view thereof;

FIG. 4 is a top elevation view thereof;

FIG. 5 is a bottom elevation view thereof;

FIG. 6 is a left side view thereof; and,

FIG. 7 is a right side view thereof.

The portion of a writing instrument shown in broken lines in the drawings is environmental matter and forms no part of the claimed design. The stippling employed in the drawings is strictly to illustrate shading and forms no part of the claimed design. 

The ornamental design for pen cap, as shown and described. 